Description:
------------
Would have added a comment to #33558

When calling a function that returns a reference using "return new SomeClass()" (or via delegate to another function that returns a reference) the "Notice:  Only variable references should be returned by reference" is triggered.

However; when a reference to $this is set in the $GLOBALS array in the contructor the notice is not triggered and both $a and $b refer to the same object as shown in the example.

Se also related #24687 and #26439 that gives weight to the desired behaviour of "return new" and "return deletegatingFactoryMethod()" really returning references 

"return null" being valid from a return-by-reference function is also desired

Reproduce code:
---------------
class FooBar {
  function FooBar() {
    // Enabling this line will prevent the E_NOTICE
    //$GLOBALS['a'] =& $this;
  }
}

function &factory() {
  return new FooBar();
}

function &deletegatingFactoryMethod() {
  return factory();
}

function &returnNull() {
  return null;
}

deletegatingFactoryMethod();
returnNull();

$b =& factory();
$b->foo = 'bar';

//var_dump($GLOBALS['a']);
var_dump($b);


Expected result:
----------------
No notices

Actual result:
--------------
The notice is triggered 4 times